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I was thinking about the Hall Effect Thrusters and how they are able to produce thrust. There's something that I don't understand: when the hollow cathodes emit electrons to neutralize the flow at the exit, there are some electrons going back to the exit of the channel. On the other hand, there are some electrons trapped in the magnetic field (radial direction) along the channel and it works as a magnetic resistance. Do you know if there's an accumulation of electrons over time in the magnetic field? If yes, can problems appear when ionizing the fluid?

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  • $\begingroup$ since same-sign charges repel, any accumulation of same-sign charges not accompanied by corresponding accumulation of the opposite sign charges is dissipating itself pretty quickly on its own. $\endgroup$ – SF. Jun 14 '16 at 9:28
  • $\begingroup$ @Nathan Tuggy, therefore there's no accumulation of electrons in the magnetic field because of the continuously dissipation between the positive-negative charges when producing thrust? The electrons emitted by the hollow cathode from outside are being atracted to the magnetic field, there are some electrons that go towards the anode. Are they entering another time into the cathode? It's like a close circuit? $\endgroup$ – Panri93 Jun 14 '16 at 9:43
  • $\begingroup$ XaviPars, I think you meant to reply to @SF., not me. $\endgroup$ – Nathan Tuggy Jun 14 '16 at 17:02
  • $\begingroup$ @XaviPars: I don't know how exactly Hall thrusters work. I just know that accumulation of any meaningful amount of single-sign charge is about impossible by all known technical means, as the repulsion force becomes enormous really fast. Any meaningful charges are storable only as differential - simultaneously positive and negative charge, for a total sum oscillating around zero. You just can't store a Coulomb of electrons without placing them really close to a corresponding amount of positive ions. And we're not even talking about intentional storage here, just accidental accumulation. $\endgroup$ – SF. Jun 14 '16 at 17:25

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